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Biomedical subjects

D Caldwell

Publications and source records attributed to D Caldwell.

At least 19 recordsLinked to original sources
PubMed2001

A depletable pool of adenosine in area CA1 of the rat hippocampus.

Adenosine plays a major modulatory and neuroprotective role in the mammalian CNS. During cerebral metabolic stress, such as hypoxia or ischemia, the increase in extracellular adenosine inhibits excitatory synaptic transmission onto vulnerable neurons via presynaptic adenosine A(1) receptors, thereby reducing the activation of postsynaptic glutamate receptors. Using a combination of extracellular and whole-cell recordings in the CA1 region of hippocampal slices from 12- to 24-d-old rats, we have found that this protective depression of synaptic transmission weakens with repeated exposure to hypoxia, thereby allowing potentially damaging excitation to both persist for longer during oxygen deprivation and recover more rapidly on reoxygenation. This phenomenon is unlikely to involve A(1) receptor desensitization or impaired nucleoside transport. Instead, by using the selective A(1) antagonist 8-cyclopentyl-1,3-dipropylxanthine and a novel adenosine sensor, we demonstrate that adenosine production is reduced with repeated episodes of hypoxia. Furthermore, this adenosine depletion can be reversed at least partially either by the application of exogenous adenosine, but not by a stable A(1) agonist, N(6)-cyclopentyladenosine, or by endogenous means by prolonged (2 hr) recovery between hypoxic episodes. Given the vital neuroprotective role of adenosine, these findings suggest that depletion of adenosine may underlie the increased neuronal vulnerability to repetitive or secondary hypoxia/ischemia in cerebrovascular disease and head injury.

Adenosine↗
PubMed1998

Abdominal wound with enterocutaneous fistula: a case study.

The care of an elderly male surgical patient with an enterocutaneous fistula located in an abdominal wound is described. The fistula is believed to have been related to multiple surgeries, wound dehiscence, and malnutrition. This article presents a brief overview of enterocutaneous fistulas and a pictorial demonstration of an alternative wound management technique that was used intermittently over several months to contain corrosive intestinal effluent until a commercial wound manager could be instituted.

Aged↗
PubMed1993

Septo-optic dysplasia: the clinical insignificance of an absent septum pellucidum.

Neurodevelopmental assessments were performed on seven patients with optic nerve hypoplasia and absence of the septum pellucidum on MRI. The evaluation included neurological status, language development, neuropsychological functioning, and behavioral and emotional adjustment. Six of the seven were found to have normal cognitive development, intact neurological status, normal language development and age-appropriate behavior. Abnormal findings included early poor motor coordination, which was felt to be closely related to decreased visual acuity, as well as subtle visual attentional problems which occurred even in patients who had normal vision in one eye. Congenital absence of the septum pellucidum was not associated with significant intellectual, behavioral or neurological deficits in the majority of these patients.

Achievement↗
PubMed1992

Continuing education requirements to maintain occupational therapy licensure.

Different states use a variety of regulatory mechanisms to monitor the quality of practice in occupational therapy. The requirement for mandatory continuing education has been adopted by fewer than half of American states, but there is reason to predict that this trend will increase. This study investigates the patterns linking licensure to continuing education and recommends actions to ensure uniformity and accountability.

Curriculum↗
PubMed1992

A comparison of neuropsychological and psychosocial functioning after prophylactic treatment for childhood leukemia in monozygotic twins.

Outcome findings based on a comprehensive battery of neuropsychological and psychosocial measurements were compared for a set of monozygotic twins. One twin had been diagnosed with acute lymphoblastic leukemia and given prophylactic treatment involving intrathecal methotrexate. Her twin sibling, who developed no signs of the disease, served as a unique control. Remarkably similar profiles were noted for the twins on tests of nonverbal intelligence, visual memory, visual attention, psychomotor speed, and mental flexibility. All performances were in the average to high average range. Significant differences were found on tasks measuring verbal abstract reasoning skills. These differences were postulated to result from prophylactic treatment, leukemia itself, or disruption in normal psychosocial development. As in previous studies, problems with auditory attention were found. However, both children displayed attentional difficulties regardless of treatment status. Emotional assessment indicated that both twins were experiencing a clinically significant level of anxiety that was postulated to play a role in reduced attention skills. Findings argue for the continued need for monitoring the neuropsychological functioning of children given prophylactic treatment and demonstrate the importance of measuring emotional factors in assessment with these children.

Affective Symptoms↗
PubMed1988

Early detection of carpal erosions in patients with rheumatoid arthritis: a pilot study of magnetic resonance imaging.

A pilot study comparing standard radiography to magnetic resonance imaging (MRI) was performed on the wrists of 10 patients with early (anatomic Stage I or II) rheumatoid arthritis (RA). MRI was found to be superior to standard radiographs in 2 respects: (1) synovial inflammation was impressively demonstrated on T2 weighted images, whereas plain films merely suggested soft tissue swelling; and (2) T1 and T2 weighted images clearly revealed erosions of several carpal bones which were not noted on standard radiographs. Although the expense of MRI currently precludes its routine use in clinical practice, the apparent sensitivity of this diagnostic modality for detecting early changes in RA might make it an invaluable tool for therapeutic decision making or for assessing response in interventional trials.

Adult↗
PubMed1987

Treatment of junctional epidermolysis bullosa with epidermal autografts.

We have successfully treated chronic facial erosions in three boys with junctional epidermolysis bullosa. In each patient, keratinocytes were harvested from the roof of suction blisters created on clinically uninvolved skin. They were grown in tissue culture on collagen sponges and grafted onto facial erosions that were previously treated with 2% mupirocin ointment. This experimental antibiotic ointment has proved efficacy in eradicating cutaneous pathogens such as Staphylococcus aureus from chronic wounds. In two patients, complete reepithelialization was achieved over 7 and 10 months, respectively, and partial reepithelialization occurred in another patient in whom treatment is ongoing. Epidermal autografts are a promising means for improving function and appearance in eroded skin caused by junctional epidermolysis bullosa.

Adolescent↗
PubMed1987

Abnormalities of plasma and erythrocyte essential fatty acid composition in epidermolysis bullosa: influence of treatment with diphenylhydantoin.

The fatty acid composition of plasma and erythrocyte phospholipids was determined in children with various subtypes of epidermolysis bullosa (EB) and in their parents. Patients with recessive dystrophic, dominant dystrophic, simplex, or junctional forms of EB had a higher percentage composition of arachidonic acid in plasma and/or erythrocyte phospholipids compared to age-matched controls. Epidermolysis bullosa patients treated with diphenylhydantoin had lower levels of arachidonic acid in plasma and erythrocyte phospholipids than did untreated EB patients. Parents of children with the recessive dystrophic or junctional EB subtypes had higher linoleic and arachidonic acids in plasma and erythrocyte phospholipids than did controls. Plasma and erythrocyte total lipids were within the normal range in children with EB. Plasma zinc was also normal but plasma copper was elevated in children with recessive dystrophic EB. We conclude that higher arachidonic acid in plasma and erythrocytes may be related to the pathology of EB.

Adult↗
PubMed1987

Interstitial deletion and ring chromosome derived from 16q.

An interstitial deletion of 16q was identified in an infant with failure to thrive, dysmorphic facies, and congenital heart defects. The mother of this infant had a similar deletion of 16q with ring formation of a fragment presumed to be derived from the deleted portion of 16q. We discuss these cases and compare them to other reports of 16q deletions.

Abnormalities, Multiple↗
PubMed1986

Grafting of skin ulcers with cultured autologous epidermal cells.

We treated five adult individuals with six full-thickness chronic ulcerations in the skin caused by venous insufficiency, sickle cell anemia, or surgical wounds. Each patient received applications to the ulcerations of sheets of autologous epidermal cells grown in culture. All patients experienced relief of pain after grafting. Four of the six ulcers healed completely in 21 to 35 days, and three of the four remained healed for up to 2 years. One ulceration recurred within 2 months. Our experience suggests that cultured autologous epidermal grafts can provide continuous covering, relief from pain, and rapid healing of chronic debilitating ulcerations of the skin.

Adult↗